Faulty special purpose vehicle control module B, often due to internal electronic failure or water intrusion; Corroded, loose, or damaged wiring and connectors on the controller area network (CAN) bus or other serial data lines to module B; Low or unstable battery voltage causing module B to transmit corrupted data frames; Software or calibration mismatch in module B after a replacement or update; Electromagnetic interference from aftermarket accessories or poor grounding affecting data integrity; A failed gateway module or main computer that misinterprets valid data from module B

DTC codes / U05xx · Network communication / U055B

U055BInvalid Data Received From Special Purpose Vehicle Control Module B

U055B means the vehicle's main engine or gateway computer received invalid or corrupted data from a special purpose vehicle control module B, which is a dedicated module for functions like suspension, braking, or auxiliary systems. The computer detected that the data frames from that module did not match the expected format or contained out-of-range values, so it flagged the communication as invalid rather than simply missing.

SystemNetwork

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaNetwork communication

Symptoms you may notice

Illumination of the malfunction indicator lamp (MIL) or a message on the driver information center
Often no symptoms besides the warning light, especially if the affected module's function is not immediately critical
Intermittent or permanent loss of the specific feature controlled by module B, such as adaptive suspension or a specialized body function
Other control modules may store communication or data integrity codes as the invalid data propagates on the network
Rough running or reduced performance if module B shares data used by the engine or transmission
A warning chime or service message related to the system that module B controls

Common causes, most likely first

Faulty special purpose vehicle control module B, often due to internal electronic failure or water intrusion
Corroded, loose, or damaged wiring and connectors on the controller area network (CAN) bus or other serial data lines to module B
Low or unstable battery voltage causing module B to transmit corrupted data frames
Software or calibration mismatch in module B after a replacement or update
Electromagnetic interference from aftermarket accessories or poor grounding affecting data integrity
A failed gateway module or main computer that misinterprets valid data from module B

How to diagnose and fix it

Perform a full scan of all modules and record all stored codes to identify which module is designated as special purpose vehicle control module B for this vehicle
Check the battery state of charge and perform a voltage drop test on the power and ground circuits to module B
Inspect the wiring harness and connectors at module B for corrosion, chafing, or loose pins, and repair as needed
Verify the software calibration of module B and update or reprogram it if a newer version is available
Clear the codes and test-drive the vehicle to see if U055B returns, noting any associated symptoms
If the code persists and wiring is confirmed good, substitute a known-good module B or perform a module swap test if feasible
Replace and reprogram module B if internal failure is confirmed, then clear codes and verify communication

What the invalid data really means

U055B is often set by a module that is still communicating but sending corrupted data, so a simple 'no communication' check will not find it; you must look at live data or use a oscilloscope on the data bus.
A weak battery or poor ground can cause module B to send invalid data without any hard fault, so always load-test the battery and check grounds before condemning the module.
Aftermarket accessories wired into the CAN bus or power circuits can introduce noise that corrupts data frames, leading to U055B even though the module itself is healthy.
The code does not always mean module B is defective; a faulty gateway or main computer that misinterprets valid data can set the same code, so swap-testing or signal analysis is needed.
On some vehicles, special purpose vehicle control module B is part of a networked system like adaptive suspension, and a failure may only show as a ride quality issue rather than a drivability problem.

Can I keep driving with U055B?

If the only symptom is a warning light and the vehicle drives normally, you can drive to a workshop for diagnosis, but avoid long trips or towing until the fault is confirmed. If the affected system involves braking, steering, or suspension, limit driving to low speeds and seek professional repair promptly.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.